SIP-T19P E2 DTMF not working with g.729

[seulater]

I have a SIP-T19P E2 that I am trying out. My system needs to use G.729 as the codec, I have the phone set up to use RFC2833 + SIP info.

I have 3 other phones on the LAN to try out as well. Grandstream, Cisco, & Polycom. Phone works fine with audio to all other phones. However the DTMF is not working correctly. From the SIP-T19P E2, to all other phones it works fine. However when any of the other phones sends the SIP-T19P E2 DTMF, i get nothing. Nothing on the LCD, and more importantly no DTMF audio.

If i switch to inband, i can hear the DTMF, but its distorted as expected when using g.729. So how can i make it sound the DTMF tones when using RFC2833 ?

[Travis_Yealink]

Hi, please help to collect the trace files, I will help you to check then.
For how to get the trace files, please refer FAQ: http://support.yealink.com/faq/faqInfo?id=311
I need TWO packages, one with T19P-E2 to other phone, another with other phone to T19P-E2, please send the trace files to support@yealink.com, we will reply you soon.